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Chapter 3

GGR107H1 Chapter Notes - Chapter 3: Northern Canada, Melilotus, Chenopodium


Department
Geography
Course Code
GGR107H1
Professor
Sarah Wakefield
Chapter
3

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CHAPTER 3: AGRICULTURAL SYSTEMS
3.1 INTRODUCTION
Agriculture of farming is the rearing of animals and the production of crop plants through cultivating the soil
It is the interaction of people and the environment, which has evolved over a period of 10,000 years
Sheep, pigs, goats, cattle, barley, and wheat were the first to be domesticated followed by six other independent origins of
agriculture
East Asia: Rice, millet, pigs, chicken, and buffalo
Central America & South America: Potato, maize, beans, squash, llama, alpaca, and guinea pigs
North America: Goosefoot and sunflower
Africa: Cattle, pigs, rice millet and sorghum
The domestication of plants and animals spread from the Near-East to the South-Eastern Europe where cultivation
improved and trading networks supported the Greek and Roman Empires.
Term agriculture is derived from both Greek and Latin origin which mean “field” and symbolized the integral link between
land-based production and modification of the natural environment.
Greek: agros
Latin: agar
The modification of land has produced the agri-ecosystem in which an ecological system is overlain by socio-economic
elements and processes. This system comprises of
Domesticated plants/animals and the people who farm them to produce food and other agricultural products
Agricultural geography looks at various aspects such as
Spatial distributions of crops and livestock
The systems of management employed
The nature of linkages (economic, social, cultural, political, ecological systems)
Food production
Food processing
Marketing
Consumption
3.2 THE AGRI-ECOSYSTEM
The physical environment (land) can be a fundamental significance to the nature of farming systems
Capital can enable the purchase of inputs that can substantially modify the physical characteristics of land
Changeable weather/hydrological cycle can present elements of risk to areas of economic activity
The environment affects the nature of farming, but in turn agriculture affects the environment
Agricultural systems are modification of natural ecosystems and is an artificial human creation. Productivity is increased
through control of soil fertility, vegetation, fauna, and microclimate

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These modifications are intended to increase the production of biomass, which produces more than the natural
environment
Environmental consequences may occur such as
Degradation of soil
Runoffs (nitrate pollution, water pollution)
Effects on wildlife
Agriculture is different from other types of economic activity as it deals with living things
Animals and plants strive on certain characteristics of the land and hence exert a strong influence on the nature and
location of agricultural production
The farmer is the essential human component that influences/determines the composition, functioning and stability of the
system
The agri-ecosystem differs from natural ecosystems due to their simplicity and small amount of diversity
Plant domestication has produced less genetic diversity compared to their wild ancestors
The biomass of herbivores (sheep, cattle, etc..) are much larger than their equal counterparts which are supported
by the natural ecosystem
The cultivation of crops through harvesting or consumption by domestic livestock, removes the energy supplied to the soil
which is normally given through dead and decaying organic matter and humus.
Agri-ecosystems require large inputs and outputs of energy from
Human and animal labour
Fuel
Seeds
Fertilizers
Herbicides
Pesticides
Machinery
Water
The most dominant natural resource to farming are climate and soils
3.3 CLIMATE AND AGRICULTURE
Climate and temperature are the two physical constraints that can affect agricultural productivity
Other constraints include
Soil type
Nutrient availability
Topography
Aspect and drainage
Climate determines the geographical regions where crops can be cultivated
Modern plant breeding has modified the amount of water plants need and the temperature in which they can sustain, but
climate still affects the geographical location in which they can be grown

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3.3.1 TEMPERATURE
Both plant and animals growth are affected by climatic variables
Solar variables
Precipitation available for transpiration
Temperature
Optimum growing conditions can be recognized when a plant gives the highest yield (largest weight of edible part of the
crop per unit area
Economically it is best to cultivate a crop in a physical region which is optimal for the plants growth
There are economic limits productions which are influenced by production costs and market demand
Increases in production cost and/or falls in price promote a contraction of the margin of cultivation toward the
optimum area
For each crop there is a temperature range within which growth and development can take place. The critical temperatures
are
The minimum, below which there is insufficient heat for biological activity
The optimum, at which rates of metabolic processes are at their maximum
The maximum, beyond which growth ceases. Higher temperatures may be harmful or lethal.
Some crops have particular temperature requirements
Low night time and higher day-time temperatures
Winter chilling before flowering and seed setting can occur
Other crops are termed photoperiodic, where day-length triggers the necessary to trigger flowering. There are four groups
that are recognised
Short-day/Long-night:
Photoperiod of under ten hours
Soybeans, millet, sweet potatoes
Occur in low latitudes where spring and autumn seasons are warm enough to allow their harvest cycle to
be completed
Long-day/Short-night
Photoperiod of over 14 hours
Small grains, timothy, sweet clover
Occur in high latitudes
Immediate day
Photoperiod of 12-14 hours
Inhibition of production, above or below these levels
Day-neutral
Unaffected by variations during the day-length
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